G'day

I tried to run my engine for the first time today since i bought it and suprise suprise it dont run. I have been workin thru the problems and have so far found that the two main elements of a running engine are missing, fire and spark. I have check to see if the fuel pump is working and it isnt, its the SU mechanical unit.

So my question is this is there any way of dismantling the pump to check if the internals are working, ie diaphragm, and what are the common causes (and best way to check them) of no spark?

Any help is much appreciated

Before you pull the pump apart....

Is there any fuel in the tank? (petrol will evaporate)
Is the fuel getting to the pump? (Rubber hoses can swell up internally or it could be blocked up with rust or dirt)

To check the pump without removing it...
Get a length of fuel hose and a coke bottle full of petrol and hook the hose to the tank side of the pump and see if the pump will work when you spin the motor over.

yeah theres fuel as the engine isnt currently in the car and therefore isnt connected to the tank so im trying to run it out of a fuel can. the hoses seem to be fine and i can blow air through them. i have tried your method for testing, thats how i know its not working , and theres no fuel being pumped so i imagine the diaphragm is stuffed.

AS for the spark side of things i have had a better look and it seems that the coil has been disconnected. I have tried to rewire it up but have had no luck in getting it to work so if anyone knows how they are wired im sure it would help.

cheers

Can you blow through the fuel pump in both directions? (stick the hose on the inlet and blow, then stick the hose on the outlet and blow)
You should only be able to blow in one direction.

The coil gets the wire from the distributor to the + side of the coil and a wire from the battery to the - side of the coil. (or the other way if the car is pos earth)

hey mate i had the same problem ages ago with my car and i just ended up fitting an electric fuel pump for like $50 and havent looked back since.

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hope be back on the road soon with a blown 1275.

morris 110, i can blow thru the pump easily in the way the petrol should flow, which i guess is a good thing, and when i blow thru the other way only a small amount of air gets thru. Does this small amount of air mean its stuffed as i imagine that its only sposed to go one way?

Yeah i thought bout fitting an electric fuel pump but would rather stay with the mechanical if i can, just an originality (and a dislike of electric components on engines) thing. However, mini4350, where did you get the pump from as the ones ive seen are twice that price?

Cheers for the help so far and keep it comin coz the old girl still aint firing.

If the pump valves are good, no air should get through that way.
Did you prime the pump (suck some fuel thru it)- makes the valves seal better.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I had the same prob, and a new SU mechanical fuel pump for $50 set me right.

When you actuate the lever on a new fuel pump, you can really hear it suck, then blow through the pump. Can you do this on your old one?

Fuel pumps seem to go bad if not used for ages. Just replace it dude.

hey micky b i bought the pump from supercheap or auto barn. I cant remember which one but that was like 2 years ago and have had a problem since.

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hope be back on the road soon with a blown 1275.

bought a new mech pump for round bout $70, can get one from Karcraft for $66, or you can buy a kit from them for less i think.

cheers for all the help guys

spent some time on the engine today, figured out the wiring for the coil thanks Morris 1100, primed the fuel pump like the doc said, gave the old girl a few sniffs of petrol down the carb and she started first go. Also, to my suprise, she ran smooth and quite and revved nicely, not bad for an engine that hasnt been run in god knows how long.

Only now ive got a new problem
I think there more petrol leaking out of the carby then there is going into the engine it seems to be coming from the top of the float bowl (which is missing a screw so was expected) and also from the spring arm coming out of the bottom of the bowl. Im guessing a rebuild kit would supply all the necessary gaskets and parts to fix this?

Once again thanks for all ya help and keep it comin as im still a long way off havin a drivable mini (altho i havent ever driven one yet so i dont know what im missin)

PS check the members gallery in the next couple of days for an update on the progress, with pics, of my Deluxe project